Shorter length moving averages are more sensitive and identify new trends
earlier, but also give more false alarms. Longer moving averages are more
reliable but less responsive, only picking up the big trends.

Use a moving average that is half the length of the cycle that you are
tracking. If the peak-to-peak cycle length is roughly 30 days, then a 15 day
moving average is appropriate. If 20 days, then a 10 day moving average is
appropriate. Some traders, however, will use 14 and 9 day moving averages for
the above cycles in the hope of generating signals slightly ahead of the market.
Others favor the Fibonacci numbers of 5, 8, 13 and 21.

100 to 200 Day (20 to 40 Week) moving averages are popular for longer cycles;

20 to 65 Day ( 4 to 13 Week) moving averages are useful for intermediate cycles; and

The simplest moving average system generates signals when price crosses the moving average:

Go long when price crosses to above the moving average from below.

Go short when price crosses to below the moving average from above.

The system is prone to whipsaws in ranging markets, with price crossing back
and forth across the moving average, generating a large number of false signals.
For that reason, moving average systems normally employ
filters to reduce whipsaws.

The popular MACD ("Moving Average Convergence
Divergence") indicator is a variation of the two moving average system,
plotted as an oscillator which subtracts the slow moving average from the
fast moving average.

Wilder moving averages are used
mainly in indicators developed by J. Welles Wilder. Essentially the same
formula as exponential moving averages, they use different weightings
— for which users need to make allowance.